Process and apparatus for making calcium cyanamid.



PROCESS AND APPARATUS FOR MAKING CALCIUM CYANAMID. APPLICATION FILED nc.3. 1917.

Patente'd @11.28, 1919..

541/0014159@ E 00x, 6g

@Miou my v jinithe artfto vwhich it appertains to make "v frnocnss niyrniifranarus .ron manine' CALCIUM fermarmi.

l Specification of Letters llatent.

cornice.

"fl )Y Gronau `nffecit,*or NIAGARA-FALLS, mentirosa, assieivon To mexican CYAN-Anm l i C OMAN LOF NEW `ZOEK, It. La comonamonormm.' l y y i raeencedaa; 28,15319.-

l applicati@ aies December e, ieri'. semina. sesam.

To all whom t may Centern: l Be it kno'ivn that I, GEORGE E. COX, a citi-y --zen of the-United States, residing at Niagara F allsyin f the fcounty of Niagaral and State of New York, have invented certain new andv .usefulImprovements in Processes of and Apparatus ,for Making Calcium Cyanainid;

and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled l and `use the saine.

' lThis invention relates to a process of and "van apparatus for improving the grade of th'eproduct, and reducing the consumption of therawniaterials in the manufacture of f commercial kcalcium cyananiid and has for f its object tov accomplish these results in a g siinplevand easy. manner.

i l e l To these ends the invention consists in the novel steps and combinations 0f steps convstituting the process all as Will be more fully l`vhereinafter ydisclosed and particularly pointed out in the claims.

. forming a part of this specification, the iig- Referring t@ the accompanying drawings,

l ure is a diagrammatic sectional vieivof a furnace suitable Vfor carrying out the invention. i;

In order that he exact process may be the better understood, it is said In the production of calcium cyanainid it has beencoiiimon practice outside the United v States to react upon calcium carbid With nitrogen at a suitable temperature, the carbid being contained in Aa foraminous vessel made o fmetal. 1 iaper,te.\:tile fabric, ora comi bination i of `these materials. The usual y I shape of this vessel has been generally cylindrical, 'the rheightbeing several timesthe` This container is inserted in a` diameter.

Q 'gas `tight n itrifying furnace of correspondingshape. theifurnace being lined with suitf' able-refractory and heat insulating material.

-.bet\veen it and theliiiing of the furnace on A free space usually surrounds the container .Qall sidegaiidg-the top of the container is left 4 open to lpermit of the easy dumping of its- Niti'o- *contents at tlie,eiid of the operation. gen is. admitted into the said free space and atytlie proper temperature reacts upon the heated 'carbid to form calcium cyaiiaiiiid.

, Thisreaction'creates in aii'v gaseous products. )vhich arisefi'om impurities in the nitrogenous gas y ,used impurities iiithe jcalcium carbid employed, and from such combustible materials as are used to linev the container, or evento make up the body of the container.

`The gases thus formed may in turn react upon the carbid to change'its character so that it no longer is capable 0f taking up nitrogen or at least to the extent it would have done, had it remained unaltered.' This vis particularly true of the-exposed top surface of the carbid in the container; so that, after the completion of the -nitrifying operation, one often finds upoh the top of the solidified ingot of cyanamid, a layer of dust portion of the mass Vof carbidv is also due to;

excessive heat losses from the somewhat unprotected surface of the carbid mass. On account of operating conditions, it has not been customary to install as much heat insulation in the cover ofthe furnace as was j provided. for instance, in the bottom, `or 4around the sides thereof, and tliemass of carbid not being thus protected even by the container onits top surface has suffered an 'excessive loss of heat.

T have found, first. that an increased'ixation of nitrogen can be obtained ifone inserts a slab of heat insulating material under the cover of the oven, but not iii contact ivitli the carbid container. vI have found further, that if a similar slab of heat insulating material is made to accurately fit the container, and to rest directly upon the top of the mass of carbid, it protectsv this top sui'- face. not oiil)v from loss of heat b vradiation. but further.` from contact with the above mentioned gasesand moisture generated b v the reaction. and I thus notonl v obtain a betteiaiixation of nitrogen. but a materially ,reduced quantity of dust on top of the ingot. A. suitable apparatus foi` carrvinL`f out the process is slioivn in the drawing in which is a metalL vessel formingthe shell et' ini ing'of thefumace, D lthe nitrogen inlet,

, E the resistor. for obtaining the necessary,

temperature' for starting the reaction and `passing through the furnace at F and G which. are electrically insulated joints. H is the container for the carbid. I is the heatinsulating slab for preventing loss of heatthro-ugh the top of the furnace,

and K is -a slab resting uponthe top ofthe carbid, on the interiorv of said container, for preventing loss of -heat-andcontacto-f the gaseous products tof the reaction with the finely divided carbid L Itis self evident that the slab I or the slab I may, be used'eitlier alone and independently of each other, or in combination asv shown in the drawing. M represents any suitable space for' the nitrogen, surrounding'the con-` tainer H. N represents openings for the' admission of nitrocen t the mass of vcarbid L, and 0 represents supports for the receptacle. H adapted to preserve the space M To illustrate the advantage of this process and apparatus it is said z-I charged over 'a period of 15 shifts when manufactl'iring .cyanamid on a commercial scale, one half of the cyan'amid ovens in the usual manner With- 'out eithertlie oven slab I or the container slab Kj all 1n accordance with the old practice; the other half of the ovens were charged with carbid of the same composition 'l found anincreazse of over 1% in the quantity of-nitrogen fixation by the carbid, a decrease of nearly 20% in the residual unfixed carbid -in the cyanamid, and an increase of 2% 1n y. the efficiency with which the carbid was used,.

I only with the slabs resting in favor of the furnaces ,using the slabs IQ v The average quantity of dust produced in the ordinary operation was 30 pounds per furnace operated. Thedust produced in the furnaces provided with slabs i averaged 7 only 5 pounds per furnace or a reduction of pounds per operation in the amount of.

dust made in favor of the furnaces operated directly on the carbid.

In the case of the combined use of the 'two slabs K and I, I similarly obtained. a greatly improved yield in quality of cyanamid, but it is not possible to present the numerical results in such a concrete form on account of the mutual influence of the two slabs. 4

One of the principal advantages obtained by the'use of a slab 'or slabs in the furnace isv in the saving of labor in removing covers and slabs, because formerly the oven cover could not be made of very light materialas it was subject to deterioiatioii;` through the .Y direct action of heat, but theffurnace slabs I and K being made of' kieselgu'hr or. other similar light Weight material, can be.

readily handled by a Isingle individual. The 70 former practice requires tivo` men and a crane foi` removing the lnecessarily heavier4 furnace covers, Whereas one man can readily handle the lighter cover B and slabs I, alld Ii-5 l It is obvious that those skilled in the art Imay' vary the details Iof the process'- as Well as of the apparatus Without departing from the spirit'of t'he invention, and therefore, I do not-Wish Ito be limited to the above dis'- 80 closui'e except as may be required by the claims.

1. The process of producing fixed lnitrogen compounds which consists in reacting 85 upon a mass of calcium carbid with nitrogen' While .preventing a substantial portion of the evolved heat from escaping from the top sur-- faceof said mass, substantially as described.

2. The-process of producing nitrogenous compounds consisting in reacting on. a mass of calcium carbid with nitrogen while substantially preventing the evolved gases from contacting with the top'surface of said mass, substantially as described. i

3. The 'process of making calcium cyanamid which consists in heating amassof calciuin carbid to a reacting` temperature in thepresence of free nitrogen; and substantially preventing the heat evolved from escaping from the top surface of said mass While also preventing the evolved gases from coming into contact with said top surface, substantially as described.- l'

4. In an apparatus for, making calcium cyanamid, the combination of' a perforated container for calcium carbid; a nitrifying closed furnace adapted to receive saidcontain'er; and .means to heat insulate the topl ysurface of the carbid in said container, during the nitrifying reaction, substantially as described.

,5. In an appara-tus for making calcium cyanamid the combination o-f a perforated container for a mass of calcium carbid; ,a 11-5 closed furnace for receiving said container; means to admit nitrogen into said furnace; means to provide a space between said con,- tainer and the inside of said furnace; means. to raise a portion of the carbid to the reacting temperature; and heat insulatingmeans located at the top of said container to prevent tlie escape of .heat from the top of said mass, substantially'as described,

'6. In an apparatus for making calcium 125 cyanamid the combination of a perforated container, for a mass of calcium carbid; a

`furnace for'receiving said container means to admit nitrogen into said furnace; means to provide a space between' said containerl 1.30

and the inside of said furnace; I n'ieans to ralse a portion of the carbid to the reacting temperature; means to prevent the evolved gases from contacting with the top surfaceof said mass; and heat insulating I neans located at the top of said furnace to prevent 'the escape of heat from the top of Said mass, substantially as described.

7. In an apparatus for making` calcium cyanami'd the combination of a furnace lined with a refractory'material; a cover for saidl j furnace; va heat insulating,f slab associated With said cover; and a 'perforated container provided with heat insulating means at'its top and adapted to hold calcium carbid 1ocated inside said furnace, substantially as described.

8. In an apparatus for making calcium cyanamid the combination of avclosed fur nace lined with a refractory material; an additional cover for said furnace; a perforated ytially closin container vadapted to Vhold calcium carbid located inside said furnace; and a heat insulating `andfgggas `excluding" slab substang said container, substantially as.'

described.

9.. The4 herein described' new articleof;l

manfact'u-re comprising a perforated conwith meanstfo admit'nitrogen to sai' carbid;

'tainery'adaptd'to hold a'mass of calcium .carbid 'in a finely -divided condition rovided and also provided a heat insulating, gas excluding slab of refractory material 'adapted to muy as described.

'est on the tcp. 'of-said mass, substan# i .3.5' In testimony whereof I- ailx my signature," 

